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BUREAU OF MINES 
INFORMATION CIRCULAR/1989 




Strontium— Uses, 
Supply, and Technology 



UNITED STATES DEPARTMENT OF THE INTERIOR 



Information Circular 9213 



Strontium— Uses, Supply, and Technology 

By Joyce A. Ober 



UNITED STATES DEPARTMENT OF THE INTERIOR 
Manuel Lujan, Jr., Secretary 

BUREAU OF MINES 
T S Ary, Director 



As the Nation's principal conservation agency, the Department of the Interior has 
responsibility for most of our nationally owned public lands and natural resources. This 
includes fostering the wisest use of our land and water resources, protecting our fish and 
wildlife, preserving the environment and cultural values of our national parks and 
historical places, and providing for the enjoyment of life through outdoor recreation. The 
Department assesses our energy and mineral resources and works to assure that their 
development is in the best interests of all our people. The Department also has a major 
responsibility for American Indian reservation communities and for people who live in 
island territories under U.S. administration. 






Library of Congress Cataloging-in-Publication Data 



Ober, Joyce A. 

Strontium : uses, supply, and technology. 

(Information circular/Bureau of Mines; 9213) 

Bibliography: p. 

Supt. of Docs, no.: 1 28.27; 9213. 

1. Strontium industry. 2. Strontium. I. Title. II. Series: Information cir- 
cular (United States. Bureau of Mines); 9213. 



-TN-295AJ4- [HD9539.S772] 622 s [338.27499] 88-600467 



For sale In iho .Su|ierinti'ndenl of Documenls, r..S. (iovernnicnl I'rijilinj; Office 
VVashinKl<in, DC 20402 



CONTENTS 



Page 

Abstract 1 

Introduction 2 

Strontium compounds and their end uses 2 

Television faceplate glass 3 

Pyrotechnics 4 

Permanent ceramic magnets 4 

Electrolytic production of zinc 4 

Paint pigments 4 

Strontium metal and alloys 5 

Superconductors 5 

Other uses 5 

World resources 5 

Recovery technology 6 

Structure of the strontium mining and chemical 

compound industries 7 

Algeria 7 

Argentina 7 

Australia 7 

Canada 7 

China 8 



Pagp 

Cyprus 8 

Federal Republic of Germany 8 

India 8 

Iran 8 

Italy 8 

Japan 8 

Madagascar 9 

Mexico 9 

Pakistan 9 

Republic of Korea 9 

Spain 9 

Turkey 9 

United Kingdom '^0 

United States 10 

U.S.S.R 10 

Secondary supply ^0 

Supply-demand relationships 10 

Research and development 12 

Legislation and government programs 14 

Strategic factors 14 

References 15 



ILLUSTRATIONS 

1. Estimated end use distribution of strontium compounds 3 

2. Simplified flowchart of two methods for strontium carbonate production 7 

3. Supply-demand relationships for strontium, 1987 11 

TABLES 



1. U.S. estimated distribution of primary strontium compounds 3 

2. Physical properties and uses of selected strontium compounds 3 

3. Estimated celestite resources and strontium carbonate production capacities worldwide 5 

4. World production of strontium minerals 6 

5. Strontium supply-demand relationships 11 

6. U.S. imports for consumption of strontium minerals 12 

7. U.S. imports for consumption of strontium metal, unwrought 12 

8. U.S. imports for consumption of strontium compounds 13 

9. Applicable tariffs for strontium minerals and compounds 14 



UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 



°c 


degree Celsius 


h 


hour 


lb 


pound 



st short ton 

st/yr short ton per year 

yr year 



STRONTIUM — USES, SUPPLY, AND TECHNOLOGY 



By Joyce A. Ober^ 



ABSTRACT 



This Bureau of Mines report attempts to present a complete picture of the state of 
the international strontium industry, including end uses, world resources, chemical pro- 
duction, supply-demand relationships, and Government programs. 

Strontium is produced from an ore, celestite, which is found in several countries; 
dominant producers are Mexico, Spain, and Turkey. The United States does not mine 
celestite domestically, but nearly 100% of its imports come from Mexico. Because of the 
good relationship between the two countries, and their close geograhic proximity, there 
is little concern over the stability of supply for the foreseeable future. Major end uses for 
strontium include color television faceplate glass, permanent ceramic magnets, and 
pyrotechnics. 



'i'h\'sieal sric'iilisl. Division ol' .MiiR-ral rdniMindiUes, I'.S. BuiX'au nl' Mines, WasliiiiiJton, DC 



INTRODUCTION 



Recent advances in materials technology have changed 
the way scientists and engineers think about the future. 
Manufacturers are no longer as reliant on traditional 
materials for their processes. In many instances new 
developments have rendered existing technology obsolete. 
Advanced or "high-tech" materials have replaced the old 
standards in many applications. Although the meanings of 
these terms are obscure at best, attempts have been made 
to define what makes a material advanced. The Bureau of 
Mines is currently using the following definition {31)''^ when 
referring to advanced materials: 

Advanced materials are those developed over the past 30 years or 
so. and being developed at the present, that exhibit 'greater 
strength/density ratios, greater hardness, and/or one or more 
superior thermal, electrical, optical, or chemical properties, when 
compared with traditional materials. Advanced metals, ceramics, 
and polymers, including composites of these, offer the promise of 
decreased energy consumption, better performance at lower cost, 
and less dependence on imports of strategic and critical materials. 
New electronic, magnetic, optical, and chemical devices, 
engineered at the molecular level, are resulting in a revolution in 
communications, data analysis, medical technology, and industrial 
processing that promises dramatic changes in manufacturing and 
numan life style. 

Further qualifications are necessary to distinguish the new ad- 
vanced materials from former advanced materials: 

• They may require advanced and sophisticated processing to at- 
tain the required purity levels and physical characteristics needed 
for use by nigh-technology industries. 

• Fabrication technology is, in many cases, the major technical 
barrier to commercial application. Application requires redesign, 
retooling, and new process development to assure uniformity, high 
yield, and reliability. Now, more than ever before, research and 
development personnel are required to participate in the pilot plant 
and production stages. 

• There is an mcreased need for materials producers and product 
manufacturers to work together from the design stage through the 
manufacturing stage. In some cases, the material may be developed 
to satisfy design demands and, in other cases, the design must be 
adapted to the properties of the material, so that an iterative proc- 
ess takes place to produce optimum properties and performance. 

Because of the large number of advanced materials in- 
cluded in the design of new and emerging weapons systems 
and other military equipment, the Department of Defense 
(DOD) identified a list of high-technology or advanced 
materials upon which to focus new studies and policies. 
DOD concerns about these materials include necessary raw 
materials for producing the advanced materials, technology 
needed for this production, and availability of raw materials 
for production. The list of 22 materials of special interest to 
DOD and described as "high-tech" metals follows: 



^Italic numbers in parentheses refer to items in the list of references at the 
end of this report. 



Indium Bismuth 

Gallium Mercury 

Rare-earth metals Selenium 

Tellurium Beryllium 

Platinum-group metals Ruthenium 

High-purity chromium Scandium 

Hafnium Zirconium 

High-purity manganese Rhodium 

Metal-matrix composites Osmium 

Rhenium Cesium 

Yttrium Strontium 

A companion list contains categories of materials and 
processes in which DOD is also interested, as follows: 

Carbon and ceramic fibers 

Compound semiconductor materials 

Large-diameter tloat-zone silicon material 

Advanced structural (high-temperature) ceramics 

Piezoelectric and other transducer and sensor 
devices 

Semiconductor injection lasers 

Diamond films for structural purposes and elec- 
tronic applications 

High-critical-temperature superconductors based 
on ceramic composites 

Large-diameter, microelectronic-circuit-quality 
Czochralski silicon wafers 

Magnetic and optical recording media 

The Bureau has traditionally aided DOD in maintaining 
up-to-date information and conducting necessary research 
on defense-related materials including traditional and ad- 
vanced materials and has begun compiling special reports 
dealing with the materials listed. Thus far reports have been 
prepared on indium, gallium, and float-zone silicon material; 
reports on the other materials on the list may be published 
in the future. The present report surveys important stron- 
tium end uses and possible future developments; also in- 
cluded are supply aspects, resource information, and 
recovery technology. 

Strontium is used in the form of chemical compounds, 
usually produced from the mineral celestite. The United 
States is presently 100% dependent on imported strontium 
minerals, most of which are imported from Mexico. 
Although possible disruptions in supply are always a con- 
cern when the United States is dependent on foreign 
sources for any material, and especially when the material is 
used in military applications, relations with Mexico are such 
that the supply of strontium is fairly well assured for the 
foreseeable future and under foreseeable circumstances. 



STRONTIUM COMPOUNDS AND THEIR END USES 



Almost everyone living in the United States has some 
strontium in their home. Approximately 2 lb of strontium 
oxide (SrO) are contained in every color television set. Many 
refrigerators' door seals are strontium ferrite magnets, and 



most small motors and loudspeakers utilize strontium 
magnets. Strontium end uses range from common, every- 
day materials to possibilities as sophisticated advanced 
materials. 



Figure 1 represents an estimated distribution of 
primary strontium compounds by end use. Close to 75% of 
all strontium consumed is in ceramics and glass manufac- 
ture, primarily in color television faceplate glass and 
ceramic ferrite magnets, and to a smaller degree in other 
ceramic and glass applications. Table 1 shows how end use 
distribution has fluctuated over the past 10 yr. It has only 
been in the past 20 yr that color television production has 
become the major consumer of strontium. 



Special end uses of strontium compounds have been 
developed because of unique properties that they possess. 
Table 2 shows some physical properties of the more common 
strontium compounds. In most cases each end use takes ad- 
vantage of a property that is uniquely appropriate for that 
specific application. 




FIGURE 1. — Estimated end use distribution of strontium 
compounds, based on contained strontium; 1987 
consumption— 19,100 tons. 



TABLE 1.— U.S. estimated distribution of primary strontium compounds, by end use, 1978-87 

(Percent) 

End use 1978 1979 1980 1981 1982 1983 1984 1985 

Electrolytic production of zinc 3 7 5 4 3 3 6 6 

Ferrite ceramic magnets 5 10 5 5 7 9 11 12 

Pigments and fillers NA 4 4 4 4 4 8 8 

Pyrotechnics and signals 17 16 12 15 15 14 14 15 

Television picture tubes 66 57 67 65 62 64 53 52 

Otfier NA 6 7 7 9 6 8 7 

Total 91 100 100 100 100 100 100 100 

NA Not available. 



1986 



1987 



6 


5 


11 


11 


7 


5 


10 


10 


60 


63 


6 


6 



100 



100 



TABLE 2.— Physical properties and uses of selected strontium compounds 



Compound 



Chemical formula 



Molecular 
weight 



Specific 
gravity 



Melting 
point, °C 



Primary uses 



Carbonate 
Chloride 
Chromate 
Nitrate . . . 
Oxalate . . 
Oxide . . . . 
Peroxide . 
Sulfate .. 

Sulfide . . 



SrCOj 147.63 

SrClj 158.53 

SrCr04 203.61 

SrfNGj); 211.63 

SrCjO.-HjO 193.64 

SrO 103.62 

SrOj 119.62 

SrSO, 183.68 

SrS 119.68 



3.70 


1,497 


3.052 


873 


3.895 


NAp 


2.986 


570 


NAp 


NAp 


4.70 


2,430 


4.56 


(') 


3.96 


1,605 



3.70 



2,000 



Ceramics and glass. 

Desensitizing toothpaste. 

.Anticorrosive paint. 

Pyrotechnics. 
Do. 

Ceramics and glass. 

Pyrotechnics. 

As celestite, raw material for all 
other compounds 

Intermediate material in conver- 
sion of celestlte to carbonate. 



NAp Not applicable. 



Decomposes on heating. 



TELEVISION FACEPLATE GLASS 

All color televisions and other devices containing color 
cathode ray tubes (CRT's) sold in the United States are re- 
quired by law to contain strontium in the faceplate glass of 
the picture tube to block X-rays; this is the largest end use 
for strontium compounds worldwide. Strontium blocks 
x-rays better than barium, which was previously used, and 
although lead is a better X-ray barrier than strontium, it 
causes a browning of the glass, which makes its use 
undesirable (4-S). Televisions produced and sold in Western 
Europe do not require strontium because they use lower 
power; barium is capable of blocking the X-ray emissions at 
the lower power level, at a lower cost (28, p. 41). 



Major manufacturers of television picture tube glass 
and other forms of color CRT's incorporate about 8% by 
weight SrO in their glass faceplate material. The strontium 
is added to the glass melt in the form of strontium carbonate 
(SrCOs), which is converted to SrO during processing (23). 
SrO is the dominant alkaline earth oxide present along with 
alkali metal oxides in picture tube glass. In addition to block- 
ing X-rays, the strontium improves the brilliance of the 
glass and improves the quality of the picture. The rear sec- 
tion of the picture tube or funnel is not adversely affected by 
the browning caused by lead, and so may not contain stron- 
tium, but some manufacturers use strontium in this part of 
the tube also. 



Trends in television production show a shift to larger, 
flatter, tubes that require thicker glass, and thus more 
strontium (JfS). Although the television industry in the 
United States is considered mature, there is a continuing de- 
mand for replacement televisions and additional sets in 
large numbers of households. The trend to personal com- 
puters and sophisticated, computerized instrumentation is 
increasing the demand for strontium in color monitors for 
these devices. Recent exchange rates have contributed to 
a trend for U.S. television manufacturers to increase 
domestic production rather than buying sets produced in 
Japan and the Far East {J,. 27). 

Other devices that contain strontium to shield X-ray 
emissions are radar screens, sonar screens, and instruments 
used in guidance and control in modern military aircraft, 
naval vessels, and weapons systems. 



PYROTECHNICS 

One of the most consistent and continuing uses for 
strontium has been in pyrotechnic devices. During this cen- 
tury, very little change has occurred in the formulas used in 
pyrotechnics to produce specific colored flames. Strontium 
burns with a brilliant red flame, and no other material has 
been found to be better in this application. The red light is 
emitted at a specified wavelength, unique to strontium com- 
pounds. Other compounds, some containing lithium, emit a 
similar red color, but other properties make their utilization 
less attractive. Lithium compounds are hygroscopic, absorb- 
ing moisture from the air and forming wet masses that are 
hard to burn (12, p. 33). 

The strontium compound used most frequently in 
pyrotechnic devices is strontium nitrate [Sr(N03)2]. Some 
strontium compounds are slightly hygroscopic, but Sr(N03)2 
takes on very little water and imparts the desired brilliant 
red. Other strontium compounds are used in pyrotechnic ap- 
plications, such as SrCOs, strontium oxalate (SrC204-H20), 
strontium sulfate (SrS04), and strontium chlorate (SrClOs), 
but Sr(N03)2 is used in significantly larger quantities than 
any of these {6). 

Pyrotechnic devices are used in military and nonmilitary 
applications. Military pyrotechnic applications that contain 
strontium include tracer ammunition, military flares, and 
marine distress signals. Nonmilitary applications include 
warning devices and fireworks. The Coast Guard requires 
certain classes of water craft to carry specific types of red 
signalling devices. Vehicles operated for interstate com- 
merce are required by law to carry certain warning devices, 
which frequently include railroad fusees containing stron- 
tium. As the name indicates, fusees are also used as warning 
devices on trains as well as by police and firefighters {1 7). 



PERMANENT CERAMIC MAGNETS 

Permanent ceramic magnets are another large end use 
for strontium compounds, in the form of strontium ferrite 
(usually SrFei20i9 or SrO»6Fe203). These magnets, original- 
ly used primarily as magnetic closures for refrigerator 
doors, are now used extensively in small direct current (dc) 
motors, especially in automotive applications such as wind- 
shield wiper motors, and in loudspeakers, other electronic 
equipment, toys, and magnetically attached decorative 
items {2). 



Strontium ferrites are used in permanent ceramic 
magnets because they have high coercive force and high 
thermal and electrical resistivity and are chemically inert 
{33). This means that they retain their magnetism well, are 
not adversely affected by electrical currents or high 
temperatures, and do not react with most chemical solvents. 
They also have a high degree of spontaneous magnetism and 
anisotropy. Spontaneous magnetism means that materials 
exhibit magnetic properties in the absence of an outside 
force, and anisotropy indicates the magnetization occurs 
along a specific direction, creating strong positive and 
negative poles. Anisotropy is enhanced by orienting tiny in- 
dividual crystals with a strong magnetic field during the 
production process, creating strong polarity in the magnets 
(2). Other properties that make the strontium magnets more 
attractive for specific applications are their resistance to 
demagnetization and their lower density, which makes them 
more desirable in applications where weight is a factor. 

Strontium ferrite magnets are generally prepared by 
mixing SrC03, iron oxide, and crystal growth inhibitors and 
presintering at 1,000° to 1,300° C. The preintered material 
is then ground to the desired particle size, mixed with a 
binder, and pressed into rigid, semirigid, or flexible bonded 
permanent magnets {25). These steps are altered according 
to the final application for the magnet. Ferrite magnets can 
be custom-formulated to achieve optimum properties for 
specific applications. 

Barium or lead can replace the strontium in ferrite 
magnets, but strontium ferrites possess the best combina- 
tion of properties necessary for superior magnets. 

ELECTROLYTIC PRODUCTION OF ZINC 

Strontium is used to remove lead impurities during the 
electrolytic production of zinc. Zinc used in die-casting 
alloys is required to contain less than 0.003% lead. Addition 
of SrCOs in sulfuric acid (H2SO4) to the electrolyte reduces 
the lead content of the electrolyte and of the zinc that is 
deposited on the cathode. 

Tests have shown that the lead is incorporated into the 
SrSOj crystal formed during the reaction of SrCOs with 
H2SO4. The precipitates formed during the reaction fall 
from the solution, removing the lead {3). This occurs because 
of the similarities in structure and reactivity between lead 
and strontium. 

PAINT PIGMENTS 

The addition of strontium chromate (SrCr04) to paint 
creates a coating that is resistant to corrosion. It is an effec- 
tive coating for aluminum, most notably on aircraft 
fuselages and ships {28, p. 67). These paints are used to 
some degree on aluminum packaging to prevent package 
corrosion. The nitrate and chloride contents of SrCr04 paint 
pigment are very strictly controlled to prevent corrosion. 

Ground celestite is sometimes used as a filler and ex- 
tender in paints, especially in Europe {28, p. 67). 

Strontium sulfide (SrS) is used as the active ingredient 
in some luminescent paints. SrS can also be used as the 
luminous pigment in phosphorescent paints. In a fine 
crystalline powder luminous SrS exhibits exceptional light- 
bearing qualities and length of afterglow without the 
dangers inherent in the radium coatings formerly used. 
Although there is little or no consumption of strontium in 
this application currently, this is a good example of stron- 
tium's unique attributes {1). 



STRONTIUM METAL AND ALLOYS 

In the metallic form strontium is a silvery white metal 
that oxidizes quickly in air to a yellowish color. It decom- 
poses water to form SrO and hydrogen and is soluble in acid, 
alcohol, and liquid ammonia. The metal is reactive and, if 
finely divided, will ignite spontaneously in air. Sr*° is a 
radioactive component of nuclear fallout which because of 
its 28-yr half-life presents a health hazard (^5, p. B-31). 

Consumption of metallic strontium is still a very limited 
factor in total strontium consumption. Small amounts of 
strontium are added to molten aluminum to improve its 
castability, making it much more suitable for casting items 
that have been traditionally made from steel. The addition 
of strontium to the melt improves the machinability of the 
casting (35) and is one of the modification techniques that 
have made it practical to use cast aluminum parts in the 
automotive industry. The reduction in car weight achieved 
by using cast aluminum parts instead of steel helps to im- 
prove energy efficiency. 

Strontium metal is produced by electrolysis of fused 
strontium chloride (SrCl2) mixed with potassium chloride or 
by reducing SrO with aluminum in a vacuum at a 
temperature at which strontium is distilled, i.e., over 1,384° 
C (29, p. 27). 

SUPERCONDUCTORS 

Some superconductor research has indicated that one 
component of high-temperature superconductors could 



eventually be SrO. Mixtures of SrO with other metallic ox- 
ides exhibit superconducting properties. This research is 
still in its early stages, and although it has received much 
media attention, it could be a long time before these 
materials achieve practical applications and commercial suc- 
cess. Very high purity SrO is believed to be essential to the 
stability of these materials, but their production is currently 
done on an extremely small scale {Jf4)- 



OTHER USES 

There are a number of other strontium end uses, 
although at present they consume only small amounts of 
strontium and strontium compounds. As mentioned 
previously, the presence of strontium in glass improves its 
brilliance. Strontium also improves the quality of certain 
ceramic glazes, without introducing the toxicity that may be 
present in glazes containing lead or barium (29, p. 9). One 
high-tech strontium ceramic is strontium titanate, used as 
substrate material for some semiconductors and in some op- 
tical and piezoelectric applications. 

SrCl2 is used in toothpaste for sensitive teeth. For this 
application impurities must be strictly controlled; limits for 
some are in the parts per million range (12). 

Strontium phosphate (SrHP04) is used in the manufac- 
ture of fluorescent lights, and the entire range of strontium 
chemicals is used in analytical chemistry laboratories (12, p. 
35). 



WORLD RESOURCES 



Strontium occurs commonly in nature, averaging 
0.034% of all igneous rock, but only two minerals, celestite 
and strontianite, contain strontium in sufficient quanitities 
to make its recovery practical. Celestite consists primarily 
of SrS04, and strontianite consists primarily of SrCOs. Of 
the two, only celestite has been found in deposits of suffi- 
cient size to make development of mining facilities currently 
attractive (29, pp. 13-14). Strontianite would be more useful 
because strontium is used most commonly in the carbonate 
form, but few deposits have been discovered suitable for 
development (7). In almost all instances, celestite deposits 
occur in remote, nondeveloped locations far from population 
centers but where inexpensive labor is available for mining. 

Huge deposits of high-grade celestite have been 
discovered throughout the world. Strontium often occurs 
along with barium and calcium, two elements with very 
similar properties, making separation difficult. Because 
removing many impurities from celestite is difficult and 
energ}' intensive, current strontium chemical producers re- 
quire material to contain at least 90% SrS04. Most currently 
operating celestite facilities can produce sufficient supplies 
with only minimal processing necessary to achieve accept- 
able specifications. Hand sorting and some washing are all 
that are necessary at many strontium mines; only a few 
operations use froth flotation or gravity separation to 
beneficiate their ore. 

Both strontium minerals occur primarily in sedimentary 
deposits, often in close proximity to limestone and barite. 
Strontium does occur in igneous rocks, but not in high 
enough concentrations to make them an acceptable source 
(7). 

Detailed information on most world resources is not 
readily available. Many of the large deposits are in remote, 
sparsely inhabited areas, and very little formal exploration 



has been done. Other deposits may be well identified, but 
are located in countries from which specific mineral infor- 
mation is not easily obtained. Table 3 indicates countries 
where strontium deposits are known to exist, as well as 
countries that produce strontium carbonate. Table 4 shows 
recent production figures of strontium minerals from these 
mines. 

TABLE 3.— Estimated celestite resources and strontium 
carbonate production capacities worldwide 

(Short tons) 

Estimated annual 
Estimated strontium carbonate 
Country resource' capacity 

Algeria' 1,000,000 

Argentina NA 

Australia NA 

Canada 1 ,000,000 

Ctiina NA 2,000 

Cyprus 220,000 

Federal Republic of Germany .... 16,500 

India' 750,000 

Iran 2,000,000 

Italy NA 

Japan 34,000 

Madagascar NA 

Mexico 2,000,000 21 ,000 

Pal<istan 750,000 

Republic of Korea' 55,000 

Spain 2,200,000 8,800 

Turkey 2,000,000 

United Kingdom' 330,000 NA 

United States' 1,500,000 11,000 

U.S.S.R NA 2,000 

Total 13,750,000 150,300 

NA Not available. 

' Resource is defined as a concentration of naturally occurring solid, 
liquid, or gaseous material in or on tfie Eartfi's crust in sucfi form and 
amount tfiat economic extraction of a commodity from tfie concentra- 
tion is currently or potentially feasible, 

' Reports indicate resource size, but actual resources are questionable. 

'Capacities of proposed production facilities. 

Sources: U.S. Department of State, Roskill Information Services, Ltd., 
Industrial Minerals, U.S. Bureau of Mines. 



TABLE 4.— World production of strontium minerals, 1977-87 

(Short tons) 

Country' 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986" 1987° 

Algeria 5,622 6,418 3,200 6,000 6,000 6,000 6,000 6,000 6,000 6,000 6,000 

Argentina 925 1,317 134 295 342 855 742 441 1,084 1,249 1,100 

Cyprus 1,543 8,119 8,000 

Iran 11,000 16,500 9,700 6,100 5,500 33,070 24,251 23,149 27,558 24,251 24,250 

Italy 770 402 1,866 1,161 7,382 3,607 456 2,866 5,083 5,144 195 

Mexico 50,302 36,563 43,562 44,931 45,574 34,917 41,343 35,264 33,601 26,774 68,597 

Pakistan 402 239 747 276 317 513 149 622 791 1,099 1,100 

Spain 8,300 15,432 19,842 20,944 39,683 38,470 38,000 29,760 46,848 38,030 38,000 

Turkey' 18,300 19,300 19,800 17,600 16,500 16,500 42,808 38,600 38,600 38,600 38,600 

United Kingdom 5,622 4,740 6,724 7.386 16,000 19,800 13,340 17,750 25,353 15,543 16,500 

Total 101,243 100,911 105,575 104,693 137,298 153,732 167,089 154,452 186,461 164,809 202,342 

° Estimated. " Preliminary. 

' In addition to countries listed, Ctiina, the German Democratic Republic, Poland, and the U.S.S.R. produce strontium minerals, but output is not 
reported quantitatively and available information is inadequate for formulation of reliable estimates of output levels. 



RECOVERY TECHNOLOGY 



Large, high-grade deposits have been identified that re- 
quire little or no beneficiation. The beneficiation that is 
necessary can usually can be done by hand sorting or simple 
washing procedures. For this reason there has been little 
development of more sophisticated, complicated, and 
ultimately more expensive techniques for beneficiation. 

Recovery technology for strontium and strontium com- 
pounds has remained virtually unchanged for most of this 
century. Two basic methods for converting celestite to 
SrCOs, the most commonly used form of strontium, have 
been used for many years, with differences occurring in in- 
dividual plants to adapt the processes to specific local prob- 
lems. In most cases these adaptations are considered pro- 
prietary by the companies involved. 

The black ash method and the soda ash method are the 
two basic recovery techniques. The black ash method, 
known alternatively as the calcining method, produces 
chemical-grade SrCOs, which is at least 98% SrCOg. The 
soda ash, or direct-conversion, method produces technical- 
grade SrCOs, which contains at least 95% SrCOs. 

The black ash method received its name because the 
first step in the procedure involves mixing the crushed and 
screened celestite with powdered coal, making a black mix- 
ture. The mixture is then reduced at about 1,100° C, expell- 
ing oxygen in the form of carbon dioxide (CO2) from the in- 
soluble SrS04 to form water-soluble SrS. The major U.S. 
producer calls this method the white ash method, because at 
this point the calcined material is light in color. 

SrS is dissolved in water, and the resulting solution is 
filtered. CO2 is then passed through the solution, or soda 
ash (Na2C03) is added. Either compound provides the car- 
bon and oxygen necessary for SrCOs to form and precipitate 
from the solution. The precipitated SrCOs is then removed 
from the solution by filtering and is dried, ground, and 
packaged. The sulfur released in the process is recovered 
either as elemental sulfur or in other byproduct sulfur com- 
pounds. 

In the soda ash method, ground celestite is washed, and 
most of the water is removed. The thickened mixture is then 
mixed with soda ash and treated with steam for 1 to 3 h. 



During this reaction time celestite and soda ash react to 
form SrCOs and sodium sulfate (Na2S04). Na2S04 is soluble, 
making it possible to separate the insoluble SrCOs by cen- 
trifuging. 

While the soda ash method is a simpler process, as 
figure 2 shows, it is not necessarily the preferred method of 
recovery because of the lower grade of the product. The 
black ash method seems to be the most common method of 
SrCOs production. 

SrCOs is the intermediate compound in the production 
of most other strontium compounds. For most applications, 
chemical-grade SrCOs, which is greater than 98'5^i pure, can 
be used without further purification. Either chemical-grade 
or technical-grade SrCOs, greater than 95"!^) pure, is ade- 
quate for transformation to other strontium compounds, 
and in the conversion processes further purification occurs. 
In some instances higher degrees of SrCOs i)urity are re- 
quired, with special emphasis placed on eliminating con- 
tamination from particular elements. 

Sr(N03)2, the second most important strontium 
chemical, is produced through the reaction of SrCOs with 
nitric acid (HNOs). Other strontium chemicals are produced 
through similar procedures of reacting SrCOs with the acid 
appropriate for the desired result. Some of the acids used 
are bromic, hydrochloric, oxalic, stearic, and tartaric {^^U. 
pp. 26-27). 

Strontium ferrite magnets are generally prepared by 
mixing SrCOs, iron oxide, and crystal growth inhibitors and 
presintering at 1,000° to 1,300° (£5, pp. 889-890). Strontium 
titanate (SrTiOs) is formed by reacting a mixture of high- 
purity SrCOs and titanium dioxide (TiO.) at 2,000° to 2,200° 
C for several hours {U, p. 35). 

Strontium metal can be produced in two ways. The 
more common method is through the thermal reduction of 
SrO and aluminum metal, subsequent distillation under high 
vacuum, and condensation of metallic strontium on a cooled 
plate. The other method is electrolysis of a fused bath of 
SrCl2 and ammonium chloride or potassium chloride {ilU, pp. 
27-28). 



BLACK ASH 



Q. 

>« 
CO 



Hfl 



or 



Nafi 



98% SrCO, 



Na^SO, 



CelestHe 
{SrSOJ 






^ 






Coa\ 




^ 






1,1 occ 











SODA ASH 











T 






^ 


CO, 




SrS 




^ 
























SrS 

+ 

H,0 










<- 


— 


CO, 




1 








<— 
r 


NBjCO, 



Na^SO, 




Precipitates from solution 



PrecipHates from solution 
FIGURE 2.— Simplified flowchart of two methods for strontium carbonate production. 



STRUCTURE OF THE STRONTIUM MINING AND 
CHEMICAL COMPOUND INDUSTRIES 



Celestite is the only strontium mineral that is commer- 
cially available. Details on celestite deposits are listed below, 
by country. Also included is a list of strontium chemical pro- 
ducers that consume strontium minerals to produce SrCOa 
and other strontium compounds. 

SrCOs is the most important of the various strontium 
compounds because it is the product that is consumed in 
most end use applications as well as being the material from 
which other strontium compounds are produced. No other 
important compounds are produced directly from the ore. 
The only other strontium compound that is consumed in 
significant quantities is Sr(N03)2. 



ARGENTINA 

Celestite mining is operated by the Argentine Mining 
Union at the San Juan Mine in the Mendoza Province. 
Celestite has also been identified at the Maria Del Carmen 
and Don Luis Mines, Mendoza Province, and the Rayoso, 
Julio, Cerro Partido, and Llao Llao Mines, Neuquen Pro- 
vince. It is unlikely that production is carried out on a 
regular basis at any of these mines. Production from the 
San Juan Mine was reported at 1,249 st in 1986, the most re- 
cent year for which information is available. Almost 60% of 
this material was exported to Brazil (38). 



ALGERIA 

Celestite is mined in Algeria from a surface deposit near 
Beni Mansour. Estimated reserves are more than 1 million 
St. The deposit is mined by Enterprise des Produits Non- 
ferreux et des Substances Utiles (ENOF) and is controlled 
by L'Enterprise Nationale de Developpement Miniere 
(Edemines), a division of Societe Nationale de Recherches et 
d'Exploitations Minieres (SONAREM). 

No strontium has been exported in recent years, but up 
to 4,000 st/yr has been exported in the past to Soviet bloc 
nations and the Federal Republic of Germany. Although the 
celestite is relatively low in grade, only about 70% SrS04, it 
is low in barite, silicate, gypsum, and iron, making it possi- 
ble to concentrate the ore to acceptable levels using only 
gravity separation. The deposit has not been fully exploited, 
but there is interest in further development (36). 



AUSTRALIA 

Celestite deposits in South Australia were discovered in 
1941 but were exploited for only a very short time (32). 
Recently, Status Minerals NL has begun exploration of 
other deposits in the desert region of the South Australian 
Great Artesian Basin. Surface deposits have been identified 
with over 90% SrS04. Once the deposit has been delineated, 
funding for development will be sought through an 
Australian stock exchange listing (18). 



CANADA 

Canada has produced celestite ore in the past from the 
McRae deposit, also known as the old Kaiser Celestite Min- 
ing Ltd. mine. It is located at Enon, Cape Breton County, 



Nova Scotia. Mineral rights are now owned by Timminco 
Metals, a division of Timminco Ltd. of Toronto. Known 
reserves are over 1 million st of celestite; grades range from 
60% to 65% SrSOj. Reopening the mine is currently being 
considered, but the low grade of the ore makes economic 
feasibility questionable. Other strontium deposits have been 
identified in British Columbia, Newfoundland, and Ontario 
(7), but none are as significant as the deposit in Nova Scotia. 

Compounds 

Timminco Metals is the largest producer of strontium 
metal in the world and the only producer of strontium metal 
in North America. A new facility has recently been com- 
pleted in Westmeath, Ontario, which increased the potential 
strontium output by over 40% (SJ^). The strontium produc- 
tion facilities in Westmeath and the old facilities in Haley, 
Ontario, produce strontium metal by the aluminothermic 
reduction of SrO as discussed previously. 



CHINA 



Mining 



Celestite is currently mined in China almost exclusively 
for domestic consumption. A new ore dressing facility with 
a capacity of 11,000 st/yr is located at the Nanjing Mine in 
the Jiang Su Province. The Nanjing deposit is reported to be 
high grade and close enough to the surface for open pit min- 
ing (37). 

Compounds 

Import data indicate that strontium chemical plants 
must exist, but no specific details are available. Japan im- 
ports SrCOs from China, and SrCOs from China has also 
been recorded in the United States. 



CYPRUS 

Celestite mining began in Cyprus in 1985 at Vassliko, 
near Limassol, in southern Cyprus. The mine is operated by 
Hellenic Mining Co. Ltd. The ore averages about 54% SrS04 
and must be concentrated to make it marketable. The ore is 
beneficiated through a flotation process to reach 94% 
SrS04. The reserves have been determined to be 220,000 st 
of celestite {13, 22). 



FEDERAL REPUBLIC OF GERMANY 

Kali-Chemie AG of Hannover produces SrCOs from im- 
ported celestite at its plant at Bad Hoenningen. The major 
Western European producer uses the black ash method in 
the recently expanded production facilities. Plant capacity is 
estimated to be 16,500 st/yr. KaH-Chemie imports most of 
its celestite from Spain and Turkey; it exports 80% to 90% 
of the production, most of which goes to the United States 
and the Republic of Korea. 

Kali-Chemie also produces strontium hydroxide and 
strontium nitrate. The nitrate is produced by its Italian sub- 
sidiary, Societa Bario e Derivati SpA, in Massa {12, p. 25). 



INDIA 

Atul Mining Works is believed to mine strontianite, 
from a mine near Bhawanimandi in Rajasthan, but no 
reports of production are available {28, p. 9). During the 
1940's, a significant celestite deposit was reported in the 
Trichinopoly district containing 500,000 to 1,000,000 st of 
96% celestite. There are no indications that the deposit has 
been developed {11). 



IRAN 

One of the world's largest celestite deposits is located in 
the northwestern part of the Dasht-e-Kavir salt desert. The 
deposit is mined by Iran Strontium Co., a subsidiary of 
Cherkate Sahami Sanati Va Maadani Irani (Simiran). 
Average SrS04 values for the deposit are reported at over 
91%, but there are unfavorably high levels of barium sulfate 
(BaS04) and calcium sulfate (CaS04). Proven reserves total 
2 million st of celestite, 475,000 st of which have no over- 
burden {30). Most of the celestite produced from this deposit 
is believed to go to the U.S.S.R. 



ITALY 



Mining 



Mining is done by Minera Chimica Farnesiana SpA in 
Tarquinia, near Rome. Most production of this 75% SrS04 
and 5% BaS04 product is sold domestically {26). Production 
capacity at the mine was recently expanded to 8,000 st/yr, 
but production has not come close to this level. Some of the 
processed ore has been exported to the U.S.S.R. {Al) Other 
deposits exist in central Sicily, although none are presently 
being mined. 

Compounds 

Sr(N03)2 is manufactured by Societa Bario e Derivati, a 
subsidiary of Kali-Chemie AG of the Federal Republic of 
Germany, at Massa. Production and capacity figures are not 
available, but it is known that most of the production goes to 
the United States {28, p. 35). 



JAPAN 

Japan is the largest consumer of SrCOs in the world, 
mostly due to its large television and electronics industry. 
No celestite is mined in Japan, but four companies produce 
SrCOs from imported celestite. 

Honjo Chemical Corp. operates a production facility for 
20,000 st/yr of carbonate at Neyagawa in Osaka using 
celestite from Spain and China. Sakai Chemical Industry 
Co. Ltd. also produces SrCOs via the black ash method in 
Osaka at a 13,000-st/yr plant, using Chinese, Mexican, and 
Spanish celestite. Japan Special Chemicals (Nihon Tokushu 
Kasei) and Dowa Chemicals also produce SrCOs, but on a 
much smaller scale; the total capacity for both companies is 
only about 1,200 st/yr. Both companies use celestite from 
Spain {If2). 

The total Japanese capacity of about 34,000 st/yr is only 
sufficient to supply half of the estimated domestic demand; 



additional SrCOa is imported from the Federal Republic of 
Germany and China (28, pp. 27-28). 



MADAGASCAR 

Celestite production has been reported in Madagascar, 
but no details are known. Exports of extremely small quan- 
tities to the United States have been reported. 



MEXICO 



Mining 



Mexico is one of the world's three largest producers of 
celestite. The most recent Directory of Mexican Non- 
Metallic Minerals Trust lists 11 companies currently mining 
celestite. Compani'a Minera La Valenciana SA (CMV) mines 
celestite from the San Agusti'n deposit near Torrebn, Com- 
pafiia Minera Ocampo SA mines a deposit near Saltillo in 
Nuevo Leon State and has some small production in 
Hidalgo, Aguascalientes, and Chihuahua States. Reserves 
of the San Agustin Mine alone have been estimated at over 
800,000 tons. Sales y Oxidos (SYOSA), which is 49% owned 
by Church and Dwight of Princeton, NY, mines west of 
Monterrey. Other small operations occur in Coahuila, 
Aguascalientes. Chihuahua, and Nuevo Leon. 

Mexican celestite is primarily high grade with only hand 
sorting required to achieve at least 92% SrS04 with low 
barium content. Abandoned mines and easily identified 
deposits that have not yet been developed are common 
throughout a large area in northern Mexico. These deposits 
have not been extensively explored, but reserves are be- 
lieved to be vast (40). 

Compounds 

SrCOs production has been a recent development in 
Mexico. Because of the huge celestite resources in the coun- 
try, this is a very attractive location for additional produc- 
tion facilities. 

After FMC Corp., a major U.S. SrCOs and Sr(N03)2 
producer, closed its California plant in 1984, Cia Minera La 
Valenciana SA brought the SrCOs processing equipment. 
The plant, which utilized the soda ash method of carbonate 
production and was converted to the black ash method, was 
relocated to Torrebn in Coahuila State, near where the com- 
pany operates a mine. The plant capacity is 13,000 st/yr. 
Shipments from the plant, targeted for the television and 
electronics industry in the Far East, commenced in May 
1987. 

SYOSA recently expanded SrCOs capacity at its plant 
near Monterrey to 8,000 st/yr. SYOSA, which produces car- 
bonate by the black ash method from celestite it mines near- 
by, is marketing its production in the United States {28, p. 
29). 

PAKISTAN 

All mines in Pakistan are the property of provincial 
governments and are operated by private companies for 
these governments. Recent celestite production figures 
have been reported for two active mines, one near Dawood 
Khail and one near Karachi {39). Tawakkal Mineral Exports 
Corp. recovers celestite from these mines in the Dadu 



District of Bind Province. No beneficiation is necessary to 
produce 94% SrSOj. Reserves of celestite have not been 
quantified at this location {lU)- Other deposits with 550,000 
tons of reported reserves have been identified in the Punjab 
Province {28. p. 13). 



REPUBLIC OF KOREA 

Celestite deposits have not been identified in Korea, but 
its growing electronics and television industry has promp- 
ted two European companies to enter joint ventures with 
Korean firms to build production facilities for SrCOs and 
BaCOs in that country. Kali-Chemie has announced a joint 
venture witn Samsung Corning Ltd., Korea, to form 
Daehan Specialty Chemicals Co. Ltd. to build a SrCOs and 
BaCOs plant on the Korean coast. The plant is to have a pro- 
duction capacity of 33,000 to 44,000 st/yr of SrCOs and 
BaCOs combined, which will be targeted for the growing 
television industry in that country. The black ash method 
will be used. 

Kofran Chemical Co., a joint venture between Rhone- 
Poulenc S.A., France, and Oriental Chemical Industry Ltd., 
Korea, has been formed to build a SrCOs and BaCOs plant in 
Inchon. Production of 22,000 st/yr of the two carbonates 
should be possible. The chemicals produced at this facility 
will also be targeted for the television industry in the Far 
East {19). 



SPAIN 



Mining 



Spain is one of the largest producers worldwide. 
Celestite is produced from the Montevive deposit, which is 
operated by Herederos de Aurelio Fajardo Vilches, with 
sales and marketing handled by Bruno S.A. Selective min- 
ing and hand sorting are all that is necessary to produce ore 
grades of over 92% SrS04, although a concentration plant is 
under construction. Reserves are believed to be at least 2.2 
million st. Most Spanish production is exported to Japan, 
although some remains in Spain and some is exported to the 
Federal Republic of Germany {28, pp. 13-15). 

Compounds 

SrCOs and Sr(N03)2 are produced by Promotora de In- 
dustria de! Sur (Proinsur S.A.) at a combined facility near 
Granada. The plant has a theoretical design capacity of 
8,800 st/yr of carbonate, but has never reached this capaci- 
ty. SrCOs is produced by the soda ash method. The plant 
also has a production capacity of about 3,000 st/yr of 
nitrate, which has not yet been fully utilized {15, p. 40). Most 
Spanish carbonate is consumed in European and Australian 
markets; about half of the nitrate is exported to the United 
States {28, p. 35). 



TURKEY 

Turkey competes with Mexico, Spain, and Iran in claim- 
ing the world's largest strontium reserves. Celestite is pro- 
duced by Barit Maden Turk AS from a mine near Sivas. 
Another mine near Sivas was formerly operated by Bilfer 
Madencilik AS, which is currently reestablishing old conces- 



10 



sions for future celestite mining. Run-of-mine ore is gravity- 
separated to produce a product with a minimum of 95% 
SrS04. Owing to the harsh cHmate in the region, the mine is 
only operated from May to October. 

Turkey's identified reserves are placed at 600,000 st, 
with further reserve potential estimated to be greater than 
'1 million st. Turkish celestite is primarily exported to the 
Federal Republic of Germany {20, p. 14). 



UNITED KINGDOM 

Celestite deposits, which occur in the Bristol area, are 
mined by Bristol Minerals Co. Ltd. The ore is crushed, 
washed, and graded to achieve a product with 95% SrS04. 
Reserve estimates range from 110,000 to 550,000 st {28, p. 
17). This is the one of the few sites where celestite deposits 
are not in remote locations {12, p. 23), and the deposits are 
being encroached on by large-scale housing developments, 
limiting their possible exploitation to the near future. 



UNITED STATES 



Mining 



Although there have been no active celestite mines in 
the United States since 1959, celestite deposits have been 
identified nationwide. During World War II, domestic min- 
ing of celestite resources occurred in Texas and California. 
U.S. celestite mines had at that time been inactive since 
World War I, with all demand for strontium minerals being 
met from foreign sources. 

Deposits were operated in 1944 near Blanket, Brown 
County, TX, in Nolan County, TX, in the Fish Mountains in 
Imperial County, CA, and near Ludlow, CA {16). At that 
time the major use for strontium chemicals was for 
pyrotechnic applications such as signal flares and tracer 
bullets required for the military effort. Immediately follow- 
ing the war, this demand disappeared, causing domestic 
production to decrease quickly and eventually taper off to 
nothing. 

Resources in the United States have been estimated at 
3.5 million st, with an identified reserve base of 1.5 million 



St. The reserve figure includes material containing no more 
than 60% SrS04, which is much too low grade to meet 
today's rigid specifications. In addition to deposits operated 
in the early 1940's, celestite has been discovei'ed in Arizona, 
Arkansas, Kentucky, Michigan, Missouri, New York, Ohio, 
Pennsylvania, Tennessee, Utah, and Washmgton {29). 

Compounds 

Chemical Products Corp. (CPC) of Cartersville, GA, is 
the only company that produces strontium compounds from 
celestite. The majority of the celestite CPC uses is from the 
Mexican deposits. CPC utilizes the black ash method of 
SrCOs production at its facility, which is estimated to have 
an annual production capacity of 11,000 st {28, p. 26). CPC 
purchased the Sr(N03)2 production facilities from FMC 
Corp. in Modesto, CA, when that company discontinued 
production in 1984. The company moved the equipment to 
Cartersville and now produces SrCNOs)^. 

Several U.S. companies produce strontium compounds 
from SrCOs. Mallinkrodt Inc., St. Louis, MO, produces 
SrCl, and Mineral Pigments Corp., Beltsville, MD, produces 
SrCrC4. A few other companies produce downstream stron- 
tium compounds, but on a very small scale. 



U.S.S.R. 



Mining 



Very little is known about Soviet production of stron- 
tium minerals. Deposits are known in the Karakum Desert 
on the Zaunguz Plateau; in Permian rock near Bashkir; in 
the caprocks of the Romy and Isachkov salt domes: in the 
Pinega area. Archangel province; in Yakutsk, eastern 
Siberia; and in Turkestan from eastern Fergana to the Cas- 
pian Sea, and from southeastern Bucharia to the Sea of 
Aral. Reserves are believed to be very large, but the ore 
grade is probably not high (21). 

Compounds 

No details are available concerning the production of 
SrCOs in the U.S.S.R. except that there is production, prob- 
ably from both domestic celestite and imports from Iran and 
Turkey. 



SECONDARY SUPPLY 



There is essentially no secondary supply for strontium 
or strontium compounds. The only instances of recycling oc- 
cur in television picture tube plants when an imperfect tube 



is produced. The faceplate of the tube is removed 
returned to the glass furnace to be remelted. 



and 



SUPPLY-DEMAND RELATIONSHIPS 



World production of strontium minerals has increased 
steadily in the past 10 yr, as demand for strontium for color 
televisions and ferrite magnets for the electronics industry 
has grown. Mineral production in market economy coun- 
tries expanded more than 80% between 1977 and 1986, thus 
increasing supply for the increased demand. Production in- 
creases reflect trends to greater production from traditional 



sources as well as recent initiation of production in a new 
facility in Cyprus. The United States has traditionally been 
the leading consumer of strontium minerals and com- 
pounds, but Japan has taken the lead in recent years. 

Twelve countries including the People's Republic of 
China and the U.S.S.R. currently produce strontium 
minerals, primarily celestite. Mexico, Spain, and Turkey are 



11 



the three largest suppliers of celestite to world markets. 
Mexico exports the majority of its celestite to the United 
States, Spain exports most of its celestite to Japan and the 
Federal Republic of Germany, and Turkey exports most of 
its celestite to the Federal Republic of Germany and the 
U.S.S.R. The United States depends entirely on imported 
minerals, most of which come from Mexico. There has been 
no U.S. celestite mining for about 30 yr. 

In recent years U.S. imports of strontium compounds 



have been rising owing to the increased demand from the 
television and electronics industries, and the decreased sup- 
ply due to the closing of the FMC plant in Modesto, CA. in 
1985. In 1987, the United States imported about 18,600 st of 
celestite and about 5,500 st of strontium compounds. 
Georgia is the only State in which SrCOs is produced, and 
because there is only one company in production, output is 
withheld fr(.)m publication to protect company proprietary 
data. 



TABLE 5. 


—Strontium supply-demand relationships, 1977-87 

(Short tons contained strontium) 








1977 1978 


1979 1980 1981 1982 1983 1984 


1985 


1986 


1987' 


WORLD PRODUCTION 



Mine production: 

United States 

Rest of world (celestite). 44,871 

Total 44,871 

Shipments of Government 

stockpile excesses 

(celestite) 

Imports (celestite and 

compounds) 19,800 

Industry stocks. Jan. 1 

(celestite) 

Total U.S. supply . . . 
Distribution of U.S. supply: 
Exports (celestite and 

compounds) 

Industry stocks, Dec. 31 

(celestite) 

Industrial demand 

(celestite and 

compounds) 19,000 

Television picture tube 

glass 12.300 

Pyrotechnic materials 3,000 

Ferrite magnets 900 

Ceramics and glass 200 

Electrolytic production of 

zinc 1,300 

Pigments 220 

Other 1,080 

Total demand (celestite 

and compounds) .... 19,000 

' Estimated. NA Not available. 

' Data may not add to total shown ow 

































44,746 


46,664 


46,433 


60,917 


68,386 


74,057 


68,516 


82,737 


72,864 


86,883 



44,746 



46,664 



46,433 60,917 



68,386 



74,057 68,516 82,737 72,864 



86,883 



COfvlPONENTS AND DISTRIBUTION OF U.S. SUPPLY 









440 


























19,800 


20,400 


22.400 


18,800 


24,300 


15,600 


22,400 


24,000 


20,500 


19,200 


24,100 


4,000 


4,800 


4,300 


6,900 


5,600 


7,700 


6,300 


5,900 


6,600 


8,600 


7,100 


23,800 


25,200 


27,140 


25,700 


29,900 


23,300 


28,700 


29,900 


27,100 


27,800 


31,200 


NA 


NA 


NA 


NA 


3,000 


300 


NA 


NA 


19 


750 


1,750 


4,800 


4.300 


5,040 


5.600 


7,700 


6,300 


5,900 


6,600 


8,600 


7,100 


9,800 



20,900 



22,100 



20,100 



19,200 



16,700 22,800 23,300 '18,500 



'20,000 



'19,700 



U.S. DEMAND PATTERN" 



13,700 14,000 

3,600 3,600 

1,000 1,100 

250 300 

1,500 2,000 

250 200 

600 900 



13,500 

2,400 

1,000 

100 

1,000 

800 

1,300 



12,400 10,300 

2,800 2,600 

1,000 1,200 

100 100 

800 500 

800 700 

1,300 1,300 



14,600 

3,200 

1,100 

200 

900 

700 

2,100 



12,300 

3,300 

2,600 

200 

1,400 
1,900 
1,600 



9,600 

2,800 

2,200 

100 

1,100 
1,500 
1,200 



12,000 

2,000 

2,200 

100 

1,100 
1,400 
1,200 



20,900 



22,100 



20,100 



19,200 



16,700 



22,800 



23,300 



18,500 



20,000 



12,400 

2,000 

2,200 

100 

1,000 
1,000 
1,000 



19,700 



ng to independent rounding. 



nv/nkw mini 


1 


<ii\/ri 




TMKWon 

picknUM 

30 3872 


1 




1 






United Kingdom 
7,900e 




United Slatea 













ProlKhnic 

ZOOOE 

SIC28S0 








18,500 


Import!, 
calesttte 
18,600 








Turkey 
19,900e 




htexlco 

27;»oe 




industry stocks 

12/31/87 

9,800 








^ 




ragnM 
ZJOOE 

SIC 32M 
























100 












10,600E 






Imports 

compoundi 
5,500 




















Ot»t% 
1,0006 






U.S. Mipoly 
31i00 




U.S. demwid 
19,700 


-♦ 


OkKMo 
pnMucKn 
(X Unc 

i,oaoE 

SIC 3333 














1 

Algmfa 




Spain 
18.700e 




















LOOOF 

SKzsie 




irxiuatry stoclcs 
1/1/87 
7,100 


►- 












Export*, 
oofnpoundt 

1,700 














1 




Cypfu* 
3,5006 




' Italy 1 








Ctrwntcunt 
8IC32S 


1 100E 1 








Key 


1 






Shipment o( 

Rtncfcpte 

•xcasset 






1 




1 




1 








World total 


E = EstimMsd 

SC - Stvdard Industrtal ClaeslflcaHon 


0««r 

ffooe 


86,900 (excluding centralty & 
DianrMd sconomv colJntli<M^ 


TswmMnt cteckf 
b^anoe 6,900 


>«• 



FIGURE 3.— Supply-demand relationships for strontium, 1987. All figures in short tons of strontium. 



12 



TABLE 6.— U.S. imports for consumption of strontium minerals, 1977-87 



Country 



1977 



1978 



1979 



1980 



1981 



1982 



1983 



1984 



1985 



1986 



1987 



QUANTITY (SHORT TONS) 



Canada 

China 

Madagascar . . . 

Mexico 

Spain 

Sweden 

Turkey 

United Kingdom 
U.S.S.R 






42,968 


(') 


18 







41,289 








183 


43,406 



367 








37,817 
829 



(') 






48,046 
1,653 







74 


32,992 
9 









(') 
47,007 
2,789 









(') 
46,873 
1,978 










37,552 










348 



30,904 

1,983 












297 

42,172 








Total 


42,986 


41,289 


43,956 


38,646 


49,699 


33,075 


49,796 


48,851 


37,552 


33,235 


42,469 


VALUE (THOUSANDS) 


Canada 

China . 










$1,885 







$8 


2,304 



22 







$2,086 
60 



1 





$2,937 
269 






$7 


2,042 
8 










$1 

3,080 

626 














$1 

3,940 

352 













$3,321 









$64 



$2,991 

342 











$38 


Madagascar 








Mexico 


$1,913 


$3 636 


Spain 








Sweden 


1 





Turkey 








United Kingdom 

U.S.S.R 


1 








Total 


1,915 


1,885 


2,334 


2,147 


3,206 


2,057 


3,707 


4,293 


3,321 


3,397 


3,674 



' Less than 1 unit. 
Source: Bureau of the Census. 

U.S. supply-demand relationships are summarized in 
table 5, and 1987 relationships are illustrated in figure 3. 
U.S. demand for strontium products in 1987 was estimated 
at 19,100 st; television picture tubes comprised about 63% 
of consumption, ferrite magnets 11%; pyrotechnic material 
10%; and other uses 16%. U.S. demand was approximately 
25% of world strontium production. Japan and the Federal 
Republic of Germany also account for large shares of world 
demand for strontium. Statistics for production of SrCOs 
are not available for most countries, because of the small 
size of the industry when compared to other commodities. 

U.S. imports of strontium minerals and compounds 
have fluctuated, reflecting changes in the structure of the 
domestic industry. The closing of the FMC facility in 1985 
caused a large drop in the amount of imported celestite, but 
since then CPC has expanded production of SrCOs and com- 
menced production of Sr(N03)2. Owing to these factors, im- 
ports of Mexican celestite are approaching the levels 



reached before the FMC shutdown. Imports of other stron- 
tium compounds have also increased in response to the lost 
production capacity from the FMC closing. Tables 6-8 show 
the trend in imports of strontium minerals and compounds 
since 1977. 

TABLE 7. — U.S. imports for consumption of strontium 
metal, unwrought, 1980-87 

(All imports are from Canada except as indicated by footnote 1) 



Year 



Pounds 



Value 



1980 
1981 
1982 
1983 
1984 
1985 
1986 



38,651 


$334,653 


33,382 


330,571 


14,633 


137,070 


1,991 


22,790 


1.424 


17,980 


9,052 


86,160 


50,928 


467,759 



1987' 



82,735 



749,026 



' Includes 11 pounds valued at $1,220 from the United Kingdom. 
Source: Bureau of the Census. 



RESEARCH AND DEVELOPMENT 

The only application for strontium in which active, well- 
publicized research has occurred recently is in superconduc- 
tors. Superconducting properties were identified in SrO at 
the National Bureau of Standards in 1964 (5), but not until 
the discovery of high-temperature superconductors in early 
1987 did more extensive research continue. The recent work 
with high-temperature materials has attracted attention 
from the media and aroused interest in developing these 
materials, which hold so much promise. 

Research being conducted at the University of Houston 
and the National Research Institute for Metals in Tsukuba, 
Japan, has identified a material containing strontium that 
exhibits superconducting properties at a temperature 
higher than that of liquid nitrogen. Superconducting 
materials that are currently being used must be cooled with 
much more expensive liquid helium to reach a temperature 
low enough to cause superconductivity {UJi). Although this 
research holds promise, many problems must be overcome 
for superconductivity to achieve widespread use. 



The earliest high-temperature materials are extremely 
brittle and have a low current-carrying capacity. To apply 
these materials in a practical fashion, they must be flexible 
enough to form wires that can be wound into coils, and 
current-carrying capacity must increase dramatically. 
Choice of substrate material, the material onto which the 
superconductor is applied, is a critical factor also. During 
processing, the superconductor must maintain its crystal 
structure and not diffuse with the substrate. Strontium 
titanate is one of the preferred substrate materials, but it is 
very expensive and some interdiffusion occurs. 

The superconducting materials containing strontium ex- 
hibit improved characteristics over the earlier compounds 
containing barium, but further research has identified other 
materials that appear even more promising. As research 
progresses, new materials will be formulated and discarded 
in quicker succession. It may be years before the optimum 
material composition for these superconductors is deter- 
mined, and strontium materials may be long rejected for 
such use by them {2Jt). 



TABLE 8.-U.S. Imports for consumption of strontium coupounds, 1977-87 





Country 


1977 


1978 


1979 


1980 




1981 


1982 


1983 


1984 


1985 


1986 


1987 








STRONTIUM CARBONATE. 


NOT PRECIPITATED 












Quantily. lb 
Canada 
Getfnany. 


Federal Republic of 




39.802 





39.683 





1,500 

79,366 


















11.023 


58 






34 



39.683 


38 


436 

39,683 

84,000 

39.683 






186.384 





39.682 









44,092 


Spain 







34,172 


United Ki 


ngdom 








Total 


39,802 


39,683 


80,866 







11.081 


34 


39,721 


163.802 


186,384 


39,682 


78,264 










Value: 

Canada 






$6,233 





$500 

14.765 



















$2,571 





2.275 






$1,745 




$11,047 





3.764 


$345 
11.233 
23,880 

9.423 







$51,256 







$11,663 








Germany, 
Mexico 


Federal Republic of 


$6,388 




$10,948 


Spain 








1,875 


United Ki 


ngdom 






6,233 



13 



STRONTIUM CARBONATE, PRECIPITATED 



Quanlity, lb: 

Canada 

China 

France 

Germany. Federal Republic of 

Japan 

Mexico 

Netherlands 

United Kingdom 



131,484 


12.139 


14,294 


317,462 











158.733 


119.049 








62.059 





2.2C5 














829,547 


37,478 




















1,596.117 




















2.292.716 


6.521,008 


7,682,615 


4,118.201 


4.485.345 


2,864,676 


938,007 


5,586,138 


9,676.889 


8,208,672 


10.120.618 











C 




















11,670 


75.527 




















354.200 


244,100 


3.739.467 


4.263.566 


2.557 











39,682 


3,120 




















5 


1 


2 


3 


12 


5,143 








27 


41,798 



Total 2,564,343 6,533,152 7,699,115 4,435,665 6,121,147 2,867,808 943,150 6,928,618 10,077,516 11,948.166 14,437.652 



alue: 

Canada 

China 

France 

Germany, Federal Republic of 

Japan 

Mexico 

Nettierlands 

United Kingdom 



Total 



$24,850 

12,481 



364,387 



13,035 

663 





$6,144 


1,190,818 



528 



$7,147 

565 



1,498,128 







399 



$70,560 



920,465 







364 







$365,442 

1,117,482 





9.826 









$797,280 





3,010 

1,864 






$290,620 



8.007 



$65,935 
253,331 


1.577.834 


130.219 







$35,169 
11,003 




2.955.649 $2,247,425 $3,247,927 





64,800 







931,557 



2,536 



8,982 

1,139.916 



27,321 



415.416 1.197,490 1,506,239 991,389 1.493.636 802.154 298,627 2,028,319 3,066,621 3,181,518 4,424.146 



STRONTIUM CHROMATE 



Quantity, lb: 

Belgium 

Canada 

France 

Germany. Federal Republic of 

Italy 

Poland 

Spain 

United Kingdom 



Total 
























5,291 


154,102 


101.853 


21,826 


553.800 


623.410 


420.370 


483.525 


867,750 


462,815 


53,010 











29,765 





41,667 








6.070 


27,006 


235,284 


222,655 


207,154 


41,005 


160,932 


661 





39.683 








14.318 


3,337 


13.228 


260.541 


59,524 


39,684 


























17.637 























35,274 



































28,660 


147,647 


187.714 


46.297 




















228 


10.155 


4.698 





453 


10,400 



483.525 873.820 539.641 330.446 



827.14 



Belgium 

Canada 

France 

Germany. Federal Republic of 

Italy 

Poland 

Spain 

United Kingdom 



Total 




$461,019 

1.561 








$591,987 
18.824 









$435,630 

7.485 








$525,411 









$1,041,755 
7,939 








$634,893 

27,714 

10,427 



21,199 



2.073 





$59,131 

240,994 

5,588 





31,034 

10.788 



$5,941 



224,149 

19,340 





161 879 

13.574 



$149,580 



231.333 

244,541 

19,456 



212,206 





$266,510 



49.275 

53.017 





53,592 

2,432 



462.580 610,811 443.115 525.411 1,049,694 696,306 347,535 



424,883 



STRONTIUM NITRATE 



$26,628 

41,509 

198 080 

47,305 







11,218 



857,116 424,826 324,740 



Quantily, lb: 

Canada , , 

f^rance 

Germany, Federal Republic of 

Ireland 

Italy 

Mexico 

Spain 

Switzerland 

United Kingdom 



80,000 

200,932 












158,731 


513,672 







425 

220 

1,872 



3,085,558 














29 
816.363 









2,334 

24,681 



5 







1,228 



363,200 



41.887 



13 







815.414 

45,194 










970,517 


865,619 









882 



935.633 



2.427.631 











1.320 



975.865 



2.103,227 

88,184 

79,971 



Total 

Value, 

Canada 

France 

Germany. Federal Republic of 

Ireland 

Italy 

Mexico 

Spain 

Switzerland 

United Kingdom 



Total 



$18,400 

61,319 












$49,591 


128.278 







$391 

533 

4,326 



792,467 














$628 
269,100 









$7,920 

766,236 










$5,774 



136,160 



14,007 



874 







$351,230 

15.622 









$417,918 

325,233 









$3,014 



371,571 


956,496 









$6,389 



398,385 



816,793 

41,762 

35.841 







1,357 



1,183,671 

2.205 

481.708 







280.932 672,403 3.088,075 816,392 2.127.020 406,328 860,608 1,836,136 3,364,146 3.248,567 1,668,941 







$8,675 



512,396 

2,000 

244,859 







79.719 177,869 



156.815 366.852 



743,151 1,341,081 1,299,170 767,930 



STRONTIUM COMPOUNDS, OTHER 



Quantily. lb: 

Belgium 

Canada 

Ctiina 

France 

Germany. Federal Republic of 

Hong Kong 

Italy 

Japan 

Netherlands 

Spain 

United Kingdom 









882 

46,495 



31.262 


1 





30,824 





199.387 

960 

79.366 

44.383 





22 





22.121 





50,484 



276,899 

44.489 





3 








82.460 



45.205 





577 








51.749 



68.342 





1,705 







4.000 

8,973 





44.092 





771 








18.963 



24.246 
366 

39,683 

16,983 



441 







22,391 





157,364 

7.726 







44.754 

65,150 



58,863 


261,795 



22.157 



407.407 





110 

792,582 





247,489 

66 



6,342 





3.429 

37.478 



2.709.526 





546,742 

694 



31,838 



Total 

Value: 

Belgium 

Canada 

China 

France 

Germany. Federal Republic of 

Hong Kong 

Italy 

Japan 

Netherlands , , 

Spain 

United Kingdom 



78,640 354.942 393,996 128,242 121,796 



57,836 100,241 



187,922 



452,719 1,453,996 3,329,707 









$2,498 

39,663 





13,961 





326 





$1,599 





97.380 

475 

17,631 

22.295 





2.443 





$1,480 





69,915 



65,419 

28,544 





540 











$66,421 





32.922 





1.783 











$16,501 





49,475 





10.484 









$5,040 

16,523 





32.693 





1.273 











$21,132 





13,698 

4.453 

14.028 

21.411 



$390 




22.913 





109.954 

11.598 





$45,026 

5,693 





55,379 





175.069 





29.695 



$43,407 





1 439 

244,367 





180,311 

1,237 



14,857 





$29,409 

4,161 



179.372 





1,260,403 

5.575 



54,892 



Total 



56.448 141.823 165.898 101.126 



76.460 



55.529 



74.722 



144.855 



310.862 485.618 1.533.812 



Source. Bureau of the Census. 



14 



LEGISLATION AND GOVERNMENT PROGRAMS 



Tariffs 

Tariffs levied against specific imported strontium com- 
pounds are listed in table 9. An ad valorem tariff is 
calculated as a percentage of the value of the goods passed 
through customs. Most Favored Nation treatment provides 
to all trading partners the same customs and tariff treat- 
ment given to all countries that fall into that category. 

The United States applies this provision to all trading 
partners except those specifically excluded by law. Coun- 
tries that are legally excluded from Most Favored Nation 
status are Afghanistan, Albania, Bulgaria, Cuba, 
Czechoslovakia, Estonia, the German Democratic Republic, 
Kampuchea, Laos, Latvia, Lithuania, Mongolia, North 
Korea, Poland, the U.S.S.R., and Vietnam. 

The International Trade Commission has investigated 
allegations pertaining to the dumping of Sr(N03)2 from Italy 
twice in the last 10 yr. The Commission unanimously deter- 
mined in 1980 that reasonable indications existed that U.S. 
industry was materially injured or threatened by injury, by 
reason of imports of strontium nitrate from Italy. These im- 
ports were deemed to be sold in the United States at less 
than fair value (8). An antidumping duty order was in- 
stituted at that time; the order was revoked in 1984 {9). 

TABLE 9.— Applicable tariffs for strontium minerals and 
compounds, January 1, 1987 

TSUS Most Favored 

Item No. Nation (MFN) Non-MFN 

Compounds: 

Carbonate: 

Not precipitated . . 421.70 Free Free. 

Precipitated 421.72 4.2% ad val. ... 25% ad val. 

Nitrate 421.74 4.2% ad val. ... 25% ad val. 

Oxide 421.76 4.2% ad val. ... 25% ad val. 

Minerals: 

Celestite 421.82 Free Free. 

Other 421.84 3.7% ad val. . . . 25% ad val. 

Other 421.86 3.7% ad val. . . . 25% ad val. 

ad val. Ad valorem. 

A similar allegation was investigated in 1987. The Com- 
mission determined that no dumping occurred during the 



period in question, June 1, 1985, to May 31, 1986. No an- 
tidumping duties were assessed (10). 

Depletion Allowance 

Depletion allowance is a proportion of a company's in- 
come derived from mining or oil production that is con- 
sidered to be a return of capital not subject to income tax. 
Depletion allowance is 22% for domestic strontium and 14% 
for foreign strontium. 

Government Stockpile 

During World War II, demand for strontium nitrate and 
other pyrotechnic chemicals expanded dramatically. At that 
time almost all celestite was imported from England and 
Germany. The supply from Germany was cut off long before 
the United States entered the war, and the supply from 
England was not very reliable owing to shipping problems 
associated with the war. For this reason exploration began 
in Mexico, and recommendations were made to amass a 
Government stockpile of the material necessary for the war 
effort. 

When the stockpile was initiated in 1942, the SrS04 con- 
tent of the celestite was specified at 92%, with a maximum 
of 4% each of BaS04 and CaS04. The most recent specifica- 
tions issued in September 1960, required the material to 
contain at least 95% SrS04 with less than 1.5% CaS04 and 
less than 2% BaS04. In 1963 a stockpile of celestite was 
determined to be unnecessary, and the General Services Ad- 
ministration began selling stockpile-grade as well as non- 
stockpile-grade celestite. In 1974 the last of the stockpile- 
grade material was sold. 

Since that time there have been virtually no sales of 
celestite from that remaining in the stockpile. The material 
is all well below stockpile specifications; all of it contains less 
than 91% SrS04 and more than 4% CaS04, and some con- 
tains almost 10% CaS04. The low grade of the celestite 
makes it very difficult, if not impossible, to sell. 



STRATEGIC FACTORS 



Stockpile Status 

The National Defense Stockpile currently contains 
13,415 st of celestite, all of which has been designated for 
disposal. The celestite in the stockpile, which is all low 
grade, has been valued at about $201,000. Under current 
policy celestite is to be eliminated from the stockpile. 

Import Dependence 

The United States is dependent on imports of celestite 
minerals. There is production of strontium compounds in 
the United States, but the raw materials for strontium pro- 



duction are 100% imported. The source for these minerals is 
almost exclusively Mexico. 

The fact that Mexico is the major U.S. supplier of stron- 
tium minerals does not lessen the import dependence, but 
does indicate that the country's sources are relatively 
secure. U.S. supplies are less vulnerable than if the source 
was more distant, or in a country with less friendly status 
than is the case between the United States and Mexico. 
Diversification of supply to other low-cost producers could 
offer some protection against future disruptions of supply. 
Development of domestic resources would decrease import 
dependence, but known deposits are not sufficiently large or 
of high enough quality to warrant such development unless 
an emergency situation cuts off U.S. supplies of celestite. 



15 



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